THE EFFECT OF HEGF AND INSULIN ON CORNEAL METABOLISM DURING OPTISOL STORAGE

We examined the effect of the growth factors, human epidermal growth f actor (hEGF) and insulin, on corneal metabolism during storage in Opti sol, a chondroitin-sulfate-(CS)-based storage medium. Paired cat corne as, in either Optisol only or Optisol with growth factor(s), were anal yzed using ex vivo P-31 nuclear magnetic resonance, after storage for 1 week at 4 degrees C. Lysosomal enzyme release into the media at the end of the storage period also was measured fluorometrically. Both epi thelial-intact and epithelial-denuded corneal pairs were examined for all conditions. Considering corneas having either intact epithelia or epithelium-denuded corneas, the addition of either growth factor alone to Optisol did not alter the relative corneal concentrations of five of the six phosphatic metabolite spectral bands measured or two metabo lic ratios calculated from these bands. Phosphodiesters, however, were significantly lower in corneas stored in Optisol containing both hEGF and insulin (23%) than in corneas stored in Optisol alone (30%). Intr acorneal pH was unaffected by the addition of growth factor(s). A sign ificantly higher release of alpha-glucosidase and alpha-mannosidase wa s noted in those corneas stored in Optisol containing bath hEGF and in sulin. Optisol maintains high-energy phosphate corneal metabolism simi lar to other CS-based media, K-Sol and Chondroitin Sulfate Corneal Sto rage Medium (CSM). The addition of the growth factors hEGF and insulin to Optisol alters corneal metabolic activity during storage in a mann er indicative of conserving corneal phospholipids.